Following [1]}, [2]}, the simplest picture of a ballistic SQPC is given by a one-dimensional, ‘‘short-limit’’ SNS model. The pair potential is taken to be a step function: bulk-like in the S region, and zero in the N region. Imperfect junction transparency is modeled by introducing scattering in the N region from a \(\delta \) -function potential
\(U(x)=V_{B}\delta (x),\) 
